\[\boxed{\mathbf{150.}}\]
\[Преобразуем\ второе\ \]
\[уравнение:\]
\[\ f(x) \bullet \varphi(x) = g(x) \bullet \varphi(x)\]
\[f(x) \bullet \varphi(x) - g(x) \bullet \varphi(x) = 0\]
\[\varphi(x) \bullet \left( f(x) - g(x) \right) = 0.\]
\[Так\ как\ \varphi(x) \neq 0:\]
\[f(x) - g(x) = 0\]
\[f(x) = g(x).\]
\[Что\ и\ требовалось\ доказать.\]